the flying machines more closely resemble? Can any bird fly for a long time without flapping its wings? [Illustration: FIG. 322.—HERRING GULL. (Order?) ] =Exercise in the Use of the Key.=—Copy this list and write the name of the order to which each of the birds belongs. (Key, page 177.) Cockatoo (Fig. 320) Sacred Ibis (Fig. 328) Screech Owl (Fig. 311) Nightingale (Fig. 325) Top-knot Quail (Fig. 329) Wren (Fig. 310) Apteryx (Fig. 318) Lyre bird (Fig. 327) Road Runner (Fig. 313) Ostrich (Fig. 332) Penguin (Fig. 330) Pheasant (Fig. 319) Wood Duck (Fig. 314) Jacana (Fig. 324) Sea Gull (Fig. 322) Heron (Fig. 315) Hawk (Fig. 312) KEY, OR TABLE, FOR CLASSIFYING BIRDS (_Class Aves_) INTO ORDERS ORDERS A_{1} =Wings not suited for flight=, 2 or 3 toes RUNNERS A_{2} =Wings suited for flight= (except the penguin) B_{1} _Toes united by a web for swimming, legs short_ C_{1} Feet placed far back; wings short, tip not DIVERS reaching to base of tail (Fig. 300) C_{2} Bill flattened, horny plates under margin of BILL-STRAINERS upper bill (Fig. 323) C_{3} Wings long and pointed, bill slender SEA-FLIERS C_{4} All four toes webbed, bare sac under GORGERS throat B_{2} _Toes not united by web for swimming_ C_{1} Three front toes, neck and legs long, tibia WADERS (shin, or “drumstick”) partly bare C_{2} Three front toes, neck and legs not long D_{1} Claws short and blunt (e, Fig. 300) E_{1} Feet and beak stout, young feathered, base SCRATCHERS of hind toe elevated E_{2} Feet and beak weak, young naked MESSENGERS D_{2} Claws long, curved and sharp, bill hooked and ROBBERS sharp D_{3} Claws long, slightly curved, bill nearly PERCHERS straight C_{3} Two front and two hind toes (Fig. 300) D_{1} Bill straight, feet used for climbing FOOT-CLIMBERS D^1 Bill hooked, both bill and feet used for BILL-CLIMBERS climbing =The Food of Birds.=—Extracts from Bulletin No. 54 (United States Dept. of Agriculture), by F. E. L. Beal. [Illustration: FIG. 323.—HEAD OF DUCK. ]